Microbubble mediated sonoporation of cells in suspension: clonogenic viability and influence of molecular size on uptake.

This work investigates whether the application of sonoporation is limited by the size of a macromolecule being delivered and by the ability of cells to proliferate following uptake. KHT-C cells in suspension were exposed to variations in ultrasound pressure (0-570 kPa) and microbubble shell-type (lipid and protein) at fixed settings of 500 kHz centre frequency, 32 micros pulse duration, 3 kHz pulse repetition frequency and 2 min insonation. Reversible permeability (P(R)), defined as the number of cells stained with FITC-dextran and unstained with propidium iodide (i.

Sonoporation by ultrasound-activated microbubble contrast agents: effect of acoustic exposure parameters on cell membrane permeability and cell viability.

This work investigates the effect of ultrasound exposure parameters on the sonoporation of KHT-C cells in suspension by perflutren microbubbles. Variations in insonating acoustic pressure (0.05 to 3.

The influence of fragmentation on the acoustic response from shrinking bubbles.

Bubble disruption is associated with the response of ultrasound contrast agents (UCAs) exposed to high acoustic pressures. This behavior is important for bubble detection techniques as well as flow quantitation and some proposed therapeutic applications. Previous work has measured acoustically the disruption threshold and postdisruption echo from populations of microbubbles.

Quantitative measurement of ultrasound disruption of polymer-shelled microbubbles.

The goal of this study was to assess the threshold of disruption and subsequent time-course of acoustic response of four experimental nitrogen-filled polymer-shelled microbubbles. Using an in vitro measurement system, a sequence of low-amplitude detection pulses measured the change in echo caused by a high-amplitude disruption pulse on a dilute suspension of bubbles. Detection pulses were transmitted 0.

A model for reflectivity enhancement due to surface bound submicrometer particles.

Submicrometer particles filled with liquid perfluorocarbon have been shown to increase the ultrasound reflectivity of surfaces onto which they bind and, consequently, are seen as potential targeted contrast agents. The objective of this study is to explain the reflectivity enhancement as a result of the presence of randomly distributed particles on a surface. A model is presented where the diffraction-weighted scattering of all particles is summed over the exposed surface.

Investigating perfluorohexane particles with high-frequency ultrasound.

Submicron particles filled with liquid perfluorocarbon are currently being studied as a potential ultrasound-targeted contrast agent. The objective of this study was to evaluate the scattering properties of these particles. Sets of perfluorohexane-filled particles of different average sizes (300 nm to 1000 nm) were produced with a constant total volume fraction.